In recent years, semiconductor memories using a nonvolatile memory, for example, a resistance change memory (magnetoresistive random access memory: MRAM, phase change random access memory: PRAM, resistive random access memory: ReRAM and the like) as a memory device attract attention.
In a resistance change memory, “1” or “0” data is determined by using the fact that the value of resistance is changed by applying a current (or a voltage). Thus, the resistance change memory includes a sense amplifier that senses a minute current difference or voltage difference of a read current read from a memory cell.